xe2x80x98Kakegawa S50xe2x80x99 originated from a hybridization made in spring 1998 in Kakegawa, Japan. The male parent was the commercial variety Liricashower Blue (U.S. Plant Pat. No. 9,885). The female parent is a breeding line known as K7-1159. K7-1159 which was an F1 plant selection from a cross between a plant line obtained from a commercial market in Brazil and the commercial variety Liricashower Rose (U.S. Plant Pat. No. 9,884). Seed from the 1998 cross was sown during the summer of 1998 and two F1 plants were selected. The two selections were intercrossed and the resulting seed bulked together to produce F2 seed. The F2 seed was sown in spring 1999 and one plant, designated as line K9-354, was selected. This line was vegetatively propagated in Salinas, Calif. in summer 1999 and again in spring 2000. In these two vegetative generations the line was evaluated and determined that the traits were firmly fixed and stable. No inherent variation or off-types have been identified.
The genus Petunia was originally established in 1803 by A. L. Jussieu, who described both P. parviflora and P. nyctaginifloa as type species. Using a non-horticultural system that selected the first mentioned species as the type species (lectotype), N. L. Britton and H. A. Brown declared P. parviflora as the type species for Petunia in 1913.
During the 1980""s and 1990, H. J. Wijsman published a series of articles regarding the ancestry of P. hybrida, the Garden Petunia, and the inter-relationship of several species classified as Petunia. These studies discovered that P. hybrida and its ancestrial species, P. nyctaginiflora (=P. axillaris) and P. violacea (=P. integrifolia), possessed 14 pairs of chromosomes while several other species, including P. parviflora, possessed 18 pairs of chromosomes. Since P. parviflora was the lectotype species for the Petunia genus, Wijsman and J. H. de Jong proposed transferring the 14 chromosome species to the genus Stimoryne. Horticulturists opposed reclassifying the Garden Petunia and in 1986, Wijsman proposed the alternative of making P. nyctaginiflora the lectotype species for Petunia and transferring the 18 chromosome species to another genus. The I. N. G. Committee adopted this proposal. By 1990 Wijsman had transferred several species, including P. parviflora (=C. parviflora) to Calibrachoa, originally established by Llave and Lexarza in 1825. Calibrachoa parviflora (=C. mexicana Llave and Lexarza) is now the type species for the genus Calibrachoa.
Classification of the current Petunia and Calibrachoa species is still in progress. New species are also being identified. Consequently a proper description has not been written for the Calibrachoa genus. Calibrachoa can, however, be distinguished from Petunia based on the higher chromosome number, chromosome morphology, plant branching habit and type of flower bud aestivation. Whereas Petunia species bear a flower peduncle and one new stem from a node, Calibrachoa bear a flower peduncle and three stems. Petunia species have a cochlear corolla bud, a single outermost petal covers the other four, radially folded and terminally contorted petals. Calibrachoa flower buds are flat with all five petals linearly folded and the two lower petals forming a cover around the three other petals and fused together.
The terminal 1.0 to 1.5 inches of an actively growing stem was excised. The base of the cuttings were dipped for 1 to 2 seconds in a 1:9 solution of Dip ""N Grow (1 part solution to 9 parts water) root inducing solution immediately prior to sticking into the cell trays. Cuttings were put into plastic cell trays having 98 cells, and containing a peat moss-based growing medium. The cuttings were misted with water from overhead for 10 seconds every 30 minutes until sufficient roots were formed. The vegetative cuttings were propagated in five to six weeks.
Rooted cuttings were transplanted and grown in 20 cm diameter plastic pots in a glass greenhouse located in Salinas, Calif. Pots contained a peat moss-based growing medium. Soluble fertilizer containing 20% nitrogen, 10% phosphorus and 20% potassium was applied once a day or every other day by overhead irrigation. Pots were top-dressed with a dry, slow release fertilizer containing 20% nitrogen, 10% phosphorus and 18% potassium. The typical average air temperature was 24C.